RE: gaps between control surfaces
I've seen planes fly with some pretty huge gaps. Sometimes it's ok, and it's not like the world will end. However, you are better off cutting off the hinges and doing it again.
While you may or may not have flutter, there are several other problems that will occur with big hinge gaps.
First, the controls will not be as effective as they would be with smaller or even sealed hinge gaps.
Second, you can have problems with the plane holding trim consistantly. This is worst on the ailerons if one side has more of a gap than the other. What happens is that depending on the amount of lift being generated, the amount of air going through the gap changes, resulting in the lift changing at different rates on the two wings, and that results in a rolling tendancy. For example, you might notice that the plane starts to roll a bit as you slow to land, or if you pull a loop, the plane might always want to roll a little.
Remember, when installing CA hinges, put the hinges in dry, put the control surface on, and when everything is in place, then apply the thinnest CA you can. Don't put CA on the hinge first and try to insert it in the wood, and don't try to attach the hinge to one side then the other.